1. Field of the Invention
The present invention relates to an injection site for the infusion of a medicament into a flow path for a parenteral fluid and, more particularly, relates to an injection site which is essentially self-priming and air-occluding and which is of extremely simple construction and easily assembled. Furthermore, the invention is also directed to an injection site of the type described herein which is especially adapted for use as an injection port of a Y-connector utilized for an intravenous administration set.
As is widely known, medicaments are frequently administered as a supplement through the employment of various devices employed in conjunction with intravenous administration sets, wherein such supplementary medicaments while in a liquid condition are usually introduced through the intermediary of a hypodermic needle which is temporarily inserted through a resealable puncturable closure provided at an injection site so as to infuse the medicament into a parenteral fluid for delivery therewith to a patient.
In general, such parenteral liquids and supplemental medicaments are intravenously administered to the patient in that the Y-connector for the intravenous administration set incorporates a plurality of communicating tubular arms, in which one arm forming a first inlet branch is connected to a source for the supplying of the parenteral fluid, the latter being continually dispensed into the tubular arm in an air-occluding flow so as to be conducted through a second tubular arm of the Y-connector discharging into a tubular conduit arrangement which may be connected to a catheter inserted into a vein of the patient. When, upon occasion, it becomes necessary to administer medications to a patient who may be in a comatose state or otherwise unable to receive such medication through oral administration, it becomes expedient to introduce any such medicament into the parenteral fluid while in the form of a fluid, for which purpose a third arm of the Y-connector, which intersects and communicates with the other arms incorporates a resealable and puncturable member, which member is generally constituted from a resilient and self-sealing, puncturable material, for example, such as rubber, through which a hypodermic needle or syringe may be temporarily inserted in order to inject a desired quantity of the medicament into the parenteral fluid flowing through the Y-connector, and thereafter withdrawn to permit the member closure to reseal itself.
A major problem frequently encountered in conjunction with injection sites of this type resides in that the Y-connector structures incorporating such injection sites which are presently in widespread use tend towards formation of air bubbles or pockets at the injection sites during the injecting of the medicament, and whereby such air must be removed in order to prevent the conveyance of potentially life-threatening entrapped air to the patient while entrained in the parenteral fluid. This frequently entails having to expend considerable periods of time in priming the Y-connector in attempting to remove any entrapped air; in essence, by tapping and/or orientation thereof in various positions by a nurse or other medical personnel so as to cause entrapped air to flow back and be discharged from the inlet for the parenteral fluid.
Moreover, various structures which are employed in the formation of such injection sites are either relatively complicated and expensive in construction and/or difficult to properly install in the Y-connector. Consequently, various attempts have been made in the technology, which are intended to simplify the structures and designs of such types of injection sites, while concurrently inhibiting the formation of potential air pockets or entrapped air bubbles which would necessitate the expenditure of considerable time and effort in having to prime the Y-connector to eliminate any air entrapped therein.
2. Discussion of the Prior Art
Sheehan, et al. U.S. Pat. No. 4,294,249 discloses a swage-molded injection site which, in one specific application thereof, may be employed in a Y-connector for an intravenous administration set, wherein the injection site includes a tubing segment constituted from a rigid and moldable plastic material. A self-sealing puncturable cylindrical member of a resilient material, such as rubber, is inserted into a housing portion in the tubing segment, with an upper edge thereof then being swaged over the periphery of the puncturable member so to cause the latter to be sealingly fixed in position within the housing. Although this particular design for an injection site allows for a simple manufacture thereof with only few components while securely sealing the puncturable member in fixed engagement within the tubular housing provided for this purpose in the Y-connector, the particular arrangement thereof allows for the entrapment of quantities of air in the interior passageway thereof communicating with the flow path for a parenteral liquid. Consequently, in order to eliminate the presence of entrapped air from the device, considerable effort must be expended by medical personnel in order to be able to remove such entrapped air to prime the device for operation with the intravenous supply of the parenteral fluid and medicament to the patient.
Efforts to eliminate such pockets of entrapped air from an injection site have been made in formulating the design of an injection port for an intravenous tube, as disclosed in Pexa U.S. Pat. No. 4,596,557. In that instance, the injection site of an intravenous tube incorporates a resilient member of a puncturable self-sealing material, such as rubber or the like, through which a hypodermic needle may be inserted for the infusion of a medicament into a flow of a parenteral fluid being intravenously administered to a patient. In the disclosed construction, the puncturable resilient member is basically a cylindrical plug which includes a tapered or obliquely angled internal end surface which terminates substantially coextensive with the flow path of the parenteral fluid being introduced therein, to thereby preclude the formation of air pockets and to resultingly reduce any necessary priming time for the device. However, the specific structure of the puncturable resilient member with an oblique internal end surface necessitates that during the installation thereof this end surface be precisely oriented and obliqued relative to the flow passageway for the parenteral fluid, and that it be anchored or adhered secured against any displacement to the wall structure of the supporting intravenous tube, inasmuch as any rotation of the resilient member subsequent to its installation would misalign the inner end surface thereof and produce a "dead space" forming a pocket of entrapped air which may be difficult to dislodge and eliminate. Moreover, this construction necessitates the utilization of additional components for securing the resilient member to the surface of its supporting tubing, which renders the entire construction cumbersome and expensive.
Further injection sites of the type considered herein are disclosed in Becker, Jr. U.S. Pat. No. 4,121,585; Zeddles, et al U.S. Pat. No. 4,005,710; Spademan U.S. Pat. No. 3,853,127; Muto U.S. Pat. No. 4,475,548; Norman, et al. U.S. Pat. No. 4,416,661; Turner U.S. Pat. No. 4,289,129; and Vaillancourt U.S. Pat. No. 4,585,435. However, none of these disclose injection sites which are as simple in construction as the inventive injection site which would readily occlude the formation of air pockets or bubbles to thereby practically eliminate or at least substantially reduce the necessity for having to prime the intravenous administration device.